A civil war has broken out among three powerful New Jersey Democrats, and it’s cast a shadow over almost everything in Trenton — from the push to legalize marijuana to a budget battle that could lead to a government shutdown.

On the other side is South Jersey power broker George Norcross, who has been a target of the probe, and his close ally, state Senate President Stephen Sweeney, who frequently feuds with Murphy.

All of three hail from the same political party, but the fight has caused their already tense relationship to explode in public last week, with Norcross calling Murphy a “liar” and “politically incompetent” in an interview with NJ Advance Media.

It comes at a tricky time, with two of Murphy’s big-ticket items — legalizing marijuana and enacting a millionaires tax — on life support and a state budget due by the end of June. And it goes beyond that as pretty much anything that happens in your state government — from property tax relief to fixing NJ Transit to curbing the staggering cost of public-employee pensions — requires these guys to get along.

So what exactly is going on? Let us break it down and explain how it affects you:

THE COMBATANTS

Phil Murphy: New Jersey’s 56th governor, he’s a former Wall Street executive who also served as U.S. ambassador to Germany under former President Barack Obama. Murphy didn’t hold elected office until he easily defeated his Republican rival in the 2017 election.

George Norcross: A wealthy insurance executive with deep ties to New Jersey politics, he’s an old-school Democratic party power broker who has long been considered the state’s most powerful unelected official because of his control of South Jersey lawmakers elected to the state Senate and Assembly. With his deep pockets, Norcross has helped fundraise, bankroll, and support Democratic races across southern New Jersey and other parts of the state.

Stephen Sweeney: As president of the Senate, the upper house of the state Legislature — a position he’s held since 2010 — he’s New Jersey’s most powerful lawmaker in Trenton, deciding what bills come up for a vote and which of Murphy’s nominees get a hearing. Sweeney and Norcross were childhood friends and remain close allies.

NJ Advance Media for NJ.com

Murphy (left) shakes hands with Sweeney at the Statehouse in Trenton earlier this year.

WHERE THE ANIMOSITY BEGAN

The three men have never been buddies.

Murphy is a more progressive Democrat, while Norcross and Sweeney are more moderate.

Both Murphy and Sweeney were expected to battle for the Democratic nomination to succeed Republican Chris Christie as governor in 2017. But Sweeney opted not to run against deep-pocketed Murphy.

Then, pro-labor Murphy refused to publicly chide the New Jersey Education Association, the state’s largest teachers union, when it spent millions to try (unsuccessfully) to oust Sweeney in the 2017 elections.

Norcross says members of candidate Murphy’s political team then tried to dislodge Sweeney as Senate president, a claim the Murphy team has denied.

After Murphy took office, he and Sweeney both insisted the strain between them was overblown by the press and touted how they worked together to institute a number of Democratic priorities.

The tension continued to bubble this year. Sweeney launched a legislative investigation into how Murphy’s administration hired a former campaign staffer accused of raping state official Katie Brennan. And he heavily criticized another Murphy-appointed official accused of unceremoniously firing workers at the New Jersey Schools Development Authority to make way for friends and family.

THE TAX BREAK FIGHT

Earlier this year, Murphy put the state’s Economic Development Authority on the defense after a scathing audit by the state comptroller criticized the EDA’s oversight of a program that aggressively handed out billions of dollars in tax incentives over the years under Christie’s leadership.

Murphy formed a special task force in the wake of the report to scrutinize the incentives. At the center of come of the task force’s investigation are disclosures on how tens of millions of dollars in tax incentives had been awarded to companies and a non-profit associated with Norcross in Camden, where is chairman of Conner Strong & Buckelew, an insurance brokerage, and chairman of Cooper Health System.

The hearing came on the heels of reports by WNYC and ProPublica, and The New York Times, which put a spotlight on how EDA incentives helped Norcross projects in Camden and other clients of Parker McKay, the New Jersey-based law firm run by Norcross’ brother Philip Norcross.

WNYC and ProPublica reported that of the $1.6 billion in tax breaks for companies that agreed to make a capital investment in Camden, at least $1.1 billion went to businesses or charities connected to Norcross or people in his orbit.

In response, Norcross has declared all-out war against Murphy. He said the commission aimed only to smear people and argued Murphy is engaged in a political feud. Norcross says he fought hard to get tax incentives to help revive Camden, his hometown, and worked within the bounds of the law to get his objectives accomplished.

Meanwhile, Sweeney countered Murphy by launching a special legislative committee to hold public hearings examining economic growth programs in New Jersey, including the EDA’s tax incentives. “It’s important to get the full picture out on this,” Sweeney told NJ Advance Media.

Murphy has said he’s simply doing his job to look into how taxpayer money was handed out and if someone should be punished if was abused. “Nobody’s getting attacked here,” he said this week.

The war of words between Murphy, Norcross, and Sweeney.

THE NASTIEST QUOTES OF THE WEEK

The battle got uglier this week.

In an interview with NJ Advance Media, Norcross called Murphy a “liar” and “politically incompetent.” He also said Murphy “thinks he’s the King of England” and his wife, First Lady Tammy Murphy, "thinks she’s the Queen of England, and they don’t have to answer to anybody. And they’ve gone out there recklessly, stupidly and incompetently time and time again.”

Murphy shrugged off the attack. “My biggest issue is: It’s very hard for an Irishman to be referred to as the King of England," the governor quipped. “I’m still coming to grips with that.”

Sweeney, meanwhile, likened the special task force to “the McCarthy hearings” in the mid-1950s.

The always-outspoken Christie — who often worked across the aisle with Norcross and Sweeney — has also gotten involved. He issued this blistering statement: “While Governor Murphy was collecting his pay-to-play gift from President Obama entertaining the wealthy of Germany at embassy parties, we were back here doing the hard work to rebuild Camden from the most dangerous city in America to the most hopeful city in America."

Chris Christie gets involved.

HOW MURPHY AND SWEENEY COULD BLOCK EACH OTHER

New Jersey’s governor is instilled with lots of power. Murphy can appoint key positions and veto bills that Sweeney wants. He can also use the bully pulpit, considering the governor has much more name recognition than the Senate president.

But Sweeney also has power. He can hold hearings, block appointees, and stonewall bills Murphy wants. In recent days, he forced Murphy’s hand to walk back a plan to take $33 million from a relief fund from firefighters, and he rejected the governor’s proposal to add $250 million more to property tax relief if lawmakers go along with a millionaires tax.

HOW THIS COULD AFFECT YOU

Legal weed

All the drama is unfolding at the same time Murphy and top lawmakers have been trying to corral enough votes in the Democratic-controlled Legislature to pass a bill to legalize recreational marijuana for those 21 and older in the state.

Hopes for that had already been dimming because lawmakers from both parties remain staunchly opposed. But sources say the tax break fight has swallowed up the oxygen in Trenton and helped erase the good will between Murphy and lawmakers.

Now, sources say the bill is likely “dead." Instead, leaders are now expected to ask New Jersey voters — probably next year — to decide whether to make weed legal. That means you may not get to smoke legally until 2021.

The state budget, property taxes, and maybe a shutdown

Murphy and Sweeney also have to work together to enact a state budget — including how much the state gives to public-worker pensions, school funding, and property tax relief in the state with the nation’s highest property taxes.

The next one is due July 1. And right now, Murphy is pushing to raise taxes on millionaires to add $447 million to the budget for increases in funding for education, transit, and pensions.

He called for the same thing last year, but both Sweeney and state Assembly Speaker Craig Coughlin, D-Middlesex, were opposed. Only a last-minute deal — which raised taxes on corporations and people making $5 million or more — avoided a government shutdown.

This time, sources say, Murphy is insisting on a millionaires tax. And again, Sweeney and Coughlin are against it, saying the state is already overtaxed and calling for government cuts instead.

If they don’t reach an agreement on the budget by the end of June, Murphy could shut down the government until one is reached. That means you may not be able to camp and relax at state parks and beaches on July 4 or renew your drivers license for a while.

Tax incentives

Murphy wants to completely revamp how New Jersey hands out tax breaks to lure companies to the state and keep others from leaving. That could mean new oversight for how your tax dollars are used by corporations.

“It’s not just a matter of doing well by some, but by all," Murphy said during a speech in New Brunswick on Friday.

But the Legislature would have to pass a bill before anything can change. That means Sweeney would need to be on board.

THIS COULD LEAD TO A PRIMARY FIGHT

Norcross hinted this week that Murphy can expect to face a challenger in the Democratic primary when he’s up for re-election in 2021. And that fueled ongoing speculation that Sweeney could be the one to do it.

Sweeney told reporters he’s not thinking about a primary challenge against Murphy — but he also didn’t rule it out. “I’m just focused on my job in front of me,” he said.

That means this likely won’t be a run-of-the-mill war of words that will fade away in short order. It’s a fight that could damage both sides and stretch on for the next few years.